The clarification of O/W emulsions to the point where they are a transparent liquid is particularly important for analytical purposes. For example, solid insoluble particles in an emulsion can, if at all, only be determined with difficulties. If the emulsion is not clarified at least to the point where it is translucent, a count of solid insoluble particles in the emulsion by e.g. optical methods is not possible.
The quantification of biological contamination in emulsions is of particular importance, since emulsion in all areas where they are employed, but in particular in food, beverages and healthcare and/or cosmetic products, may become unusable and/or a health risk when the contamination by bacteria, yeast or algae exceeds certain threshold values.
With respect to determination of living microorganisms in emulsions it is highly desirable, to have a reagent and method which can clarify the emulsion into a completely transparent liquid in as short a time and at as low a temperature as possible in order to allow a fast and correct direct quantitative determination of the organisms e.g. by optical means. If the clarification of the emulsion is not complete, the counts may be incorrect e.g. due to remaining particle-like aggregates, and if the temperature is too high and the processing time is too long, the microorganisms may on one hand be destroyed, or, on the other hand, may proliferate both leading to false test results.
In particular with respect to milk which is a fat-in-water emulsion there are a number of methods described in the prior art which aim at the clarification of milk to form a transparent liquid (see e.g. U.S. Pat. No. 3,679,365 A, EP 0246987 B1, DE OS 17089 A1, DE 4017398 A1 and EP 0573054; the entire disclosure of all of these documents is herewith incorporated by reference into this specification). However, none of these methods proved to be satisfying under conditions of routine use.
It was the aim of the present invention to find a more satisfying solution for turning emulsions into transparent liquids.